Cylinder surfacing tool



March 29, 1949.

H. R. BILLET ER CYLINDER SURFACING TOOL Filed Sept. 9, 1946 I N V EN iOR. Herigfiaberifi Patented Mar. 29, 1949 UNITED STATES ATENT OFFICE CYLINDER SURFAOING TOOL Illinois Application September 9, 1946, Serial No. 695,707

3 Claims.

My invention relates to cylinder surfacing tools of the type disclosed in 'Patent No. 2,118,720 granted to Herman W. Zimmerman on May 24, 1938, and. it has to do particularly with drive means therefor.

In the building of new cylinders or the servicing of old ones, the ideal initial cylinder wall surface, while appearing quite smooth to the eye, is actually minutely roughened in that it consists of very fine, diagonal crisscross lines. This surface is conducive to rapid wear-in and seating of piston rings and aids in the maintenance of a desired oil film on the cylinder wall. Cylinder surfacing tools, such as shown in said Zimmerman patent, are particularly well suited for resurfacing small cylinders or bores; but, they tend to develop excessive vibration and chatter in the resurfacing of large bores (for example, those exceeding four inches in diameter), especially when driven at high speed, so that the desired finish is not produced thereby defeating the purpose of the resurfacing operation.

One of the objects of this invention is to provide a tool which is adapted for the resurfacing of large bores, and by which the foregoing objectionable condition is eliminated.

Another object is to provide an improved cylinder surfacing tool which is simple in construction and inexpensive to manufacture, and which is adapted to perform a resurfacing operation with maximum efiiciency even in the hands of unskilled operators.

Still another object is to provide an improved drive means for cylinder surfacing tools.

A further object is to provide a cylinder surfacing tool by which the desired wall surface in large bores is produced with the tool driven at high speed.

An additional object is to eliminate vibration and chatter in cylinder surfacing tools.

Another object is to provide a balanced drive for cylinder surfacing tools thereby eliminating vibration and chatter in all tools when driven at various speeds.

Other objects and advantages will become apparent as this descrition progresses and by reference to the drawings wherein- Figure 1 is a longitudinal, sectional view taken substantially on line l-l of Fig. 2, and showing one form of tool embodying my invention as applied to a cylinder;

Fig. 2 is a top plan view of the tool shown in Fig. 1, with part of its driving connection being shown in section; and

Fig. 3 is a detached elevatlonal view, partially 2 in section, taken substantially on line 33 of Fig. 2.

In carrying out my invention, I employ a tubular body supporting a plurality of circumferentially-spaced cylinder surfacing elements, the body being driven from an internal mid-point of the body so that rotating force is applied to the tool at about the center of inertia thereof. In this way, in surfacing large bores, even with the tool driven at high speed, a balanced drive is provided and vibration and chatter are eliminated or minimized to such an extent that the desired surface with its diagonal, crisscross lines free from chatter marks, is produced.

The tool shown in the drawing is adapted for surfacing the, wall of a cylinder 4 and it comprises an elongated tubular metallic body 5 open at both ends. The body 5 is adapted to support a plurality (preferably, but not necessarily, four) of surfacing units 6 arranged in oppositely disposed pairs. For this purpose, the body 5 is provided with four equally spaced, longitudinallyextended channels I in its outer surface, which channels are of rectangular shape in cross section with their median lines in radial direction offset forwardly of the tool radius and passing parallel therewith and in the direction of rotation (see arrow in Fig. 2) to avoid any tendency of the surfacing units to bind against the cylinder wall 4 as more fully explained in Patent No. 1,987,457 granted to said Herman W. Zimmerman on January 8, 1935.

The surfacing units 6 are of identical construction except that one pair is adapted to support abrasive surfacing elements 8 and the other pair supports non-abrasive guide elements 9. Each surfacing unit 6 includes a channeled carrier member I6 in which the abrading and guiding elements 8 and Q, respectively, are securely mounted. Each carrier member at its opposite ends is provided with a pair of spaced lugs or ears H to which suitable carrier supporting means is secured.

The carrier supporting means takes the form of a pair of bowed leaf springs I2, one end of each of which is pivotally secured between the carrier lugs H by a bolt, or the like, E3. The leaf springs i2 are of a width substantially equal to the width of the body channels 7 and the other ends of such springs are secured in the channels 1, at spaced points therealong, by suitable screws or studs M. The body-mounted end of the upper-. most leaf spring I2 is secured adjacent the upper end of the body 5 and the corresponding end of the other or lower leaf spring I2 is secured to the body at a point spaced a distance equal to the distance between the pivots at the other ends of the leaf springs so that all carriers ID are normally supported in parallel relationship. The leaf springs I2 are bowed inwardly toward the body so that normally they tend to urge the carriers toward their fully expanded condition.

The tool may be inserted in the cylinder 4 by collapsing the carriers It] to a diameter permitting of their insertion therein; and, when the tool is inserted in the cylinder, the springs l2 urge the carriers ID to a position wherein the abrading and guiding elements 8 and 9 contact the cylinder wall under compression and constantly exert an eXpanding pressure thereon. However, the springs l2 are of comparatively light weight so as to exert only sufiicient pressure to apply a scouring action in which the desired diagonal crisscross lines in the surface are obtained. The pivotal connection between the carriers in and springs l2 permit the surfacing units to self-adjust themselves to the cylinder wall surface and thereby accommodate irregular conditions therein.

In a tool of this kind When used to resurface cylinders having large bores, for example, those in excess of four inches in diameter, there is a tendency toward vibration and chatter with the result that the desired diagonal crisscross lines are not formed in the surface being treated. This is true particularly when such tools are driven at high speeds. According to my invention, this condition is overcome by providing a balanced drive for the tool body. Specifically, to this end, the inner wall of the tool body 5 has different internal diameters, the diameter of the lower portion 5a being greatest, the diameter at the midportion 5b being slightly less, and the diameter of the upper portion 5c being smallest to provide between the portions 5b and 50 a shoulder 65. The mid-diameter portion 5b of the body 5 is adapted to receive a cylindrical drive disc l6 the periphery of which, except for the grooved portion I8 therein, being knurled as at ii. The disc l6 fits tightly within the body wall portion 51) and this fit, together with the knurled surface I! which tends to bite into the wall of the body secures the disc against rotation relative to the body. The disc is further fixed in place by upsetting the metal of the body wall therein as at 18a (Fig. 3).

The disc I6 is provided on its upper face with an integral knob-shaped drive head l9 having therein a diametrically disposed drive pin 26, the opposite ends of which project slightly beyond the side wall of the drive head iii. The drive head I9 is adapted to be received in a socket 2| on the lower or forward end of a drive shaft 22, the upper end of which is connected to a drive member 23 carried by any suitable power driving means such, forexample, as an electric drill (not shown). The socket 2i is provided with a pair of diametrically opposed bayonet slots 24 adapted to receive the projecting ends of the drive head pin 20. By engaging the drive pin 28 in the bayonet slots 24 in the usual manner, the parts are connected for rotatable as well as reciprocable drive. It will be noted that the knob-like shape of the drive head I9 provides such clearance between the drive socket 2| and such head to permit of universal action therebetween thereby accommodating for disalignment between the drive and tool.

When using the tool shown, it is first inserted in the cylinder 4 and is then driven both ro- FIE tatably and then reciprocably by the power means under the control of the operator. This action may be accomplished either manually or it may be carried out entirely by mechanical means. As the tool is operated, any disalignment that may occur is compensated for by the universal driving connection above described. The abrading and guiding elements adjust themselves to the inner wall of the cylinder under the influence of the springs l2 and the particular mounting employed.

It is believed that the operation and advantages of this invention will be obvious from the foregoing. Tools of proper size for surfacing large cylinders or bores may be operated at high speeds without detrimental vibration and chatter, and the ideal cylinder wall surface may be uniformly attained in treating successive cylinders. The tool, while quite simple in construction, is very rugged and is capable of withstanding the strains and stresses imposed thereon in the surfacing operation. These advantages are attained by the balanced drive effected by locating the driving point substantially at the mid-point of the body as described.

I claim:

1. A cylinder surfacing tool comprising an elongated tubular body member, a plurality of elongated abrasive elements, resilient means connected at one end to said abrasive elements and at the other end to said body member for mounting said abrasive elements on said body member in parallelism with each other and with the axis of said body member, a drive shaft, and means for pivotally and removably connecting said drive shaft to said body member including a disc element mounted within said body member intermediate the ends of said resilient mounting means, a universal drive connector on said disc, a drive pin. carried by said drive connector, and a universal drive connector on said drive shaft adapted to be releasably engaged with said disc drive connector.

2. A cylinder surfacing tool comprising a tubular body, a plurality of cylinder surfacing elements, means for mounting said surfacing elements on said body, including a pair of resilient support members for each surfacing element in spaced relation at one end to said body and at the other end to the respective surfacing ele-- ment, said support members being adapted to support said surfacing element in parallelism with respect to each other and to the axis of said body, and means for driving said body and the members carried thereby comprising a drive element fixed internally of said body at a point between the body-connected ends of said support members and substantially at the center of inertia of all of the members driven by said driving means, a universal drive connector on said drive element, a drive shaft adapted to pass through the upper end of said body member in spaced relation to the internal wall thereof, and a universal drive connector on the body-connected end of said shaft adapted to engage said drive connector on said body-carried drive element.

3. A cylinder surfacing tool comprising an elongated tubular body having a bore of one diameter in one end, a bore of slightly less diameter at its mid part and a bore of still less diameter at its other end providing an annular shoulder between the smaller and mid bore portions, cylinder surfacing elements, means for resiliently supporting said surfacin elements on said body for expansion and contraction movements away 6 from and toward said body member, and driving means including an annular drive disc mounted REFERENCES CITED in said mid bore portion in abutting relation to Th foll win r ferences are of record in the said shoulder means between said disc and said l Of h P n mid portion for permanently fixing said disc 5 UNITED STATES PATENTS therein, a universal drive connector on the upper Number Name Date face of said disc within said body, a drive shaft, a universal connector on the lower end of said 3 1 F1055 June 14, 1932 drive shaft and adapted to be detachably con- 2,118,720 Zimmerman May 24, 1933 nected with said disc-carried drive element for 10 imparting rotary and longitudinal reciprocating movements to said body as said drive shaft is rotated and reciprocated longitudinally.

HENRY ROBERT BILLETER. 

